Light emitting apparatus

ABSTRACT

A sealing member for a short-wavelength light emitting element comprises a main agent and a curing agent. The main agent comprises a first component of an alicyclic epoxy produced by hydrogenating an aromatic epoxy, preferably a bisphenol A epoxy, and a second component of an alicyclic epoxy having a lower molecular weight than the first component. The mixing amount of the second component is not less than 10% by weight and less than 30% by weight based on the main agent.

[0001] The present application is based on Japanese Patent ApplicationsNo. 2002-016181 and No. 2002-016182, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a light emitting apparatus. Moreparticularly, the invention relates to an improvement in a sealingmember for a light emitting apparatus using a group III nitride compoundsemiconductor light emitting element (hereinafter referred to simply as“light emitting element,” such as LED, as a light source.

[0004] 2. Related Art

[0005] In conventional light emitting apparatuses, an LED is mounted ona cup part in a mount lead, and the LED is connected to an inner leadthrough an electrically conductive wire. The LED is covered, togetherwith the electrically conductive wire, a part of the mount lead, and apart of the inner lead, with a sealing member formed of a lighttransparent resin.

[0006] In the light emitting apparatuses having the above construction,it is common practice to form the sealing member using a transparentepoxy resin. When light emitting elements, which emit short-wavelengthlight, are used with the epoxy resin as the sealing member, a change incolor (discoloration) of the sealing member occurs. This color changehas been estimated to be attributable to a double bond in the epoxyresin, and, to solve this problem, the use of an alicyclic epoxy resinhas been proposed in Japanese Patent Laid-Open No. 274571/1999.

[0007] The use of the alicyclic epoxy resin can certainly improve theresistance to discoloration of the sealing member. The alicyclic epoxyresin, however, causes a deterioration in mechanical and physicalproperties of the sealing member, for example, due to very high curingspeed and the occurrence of distortion after curing, resulting inincreased susceptibility to cracking of the sealing member.

[0008] In view of these points, the present applicant has proposed inJapanese Patent Laid-Open No. 196642/2001 the use, as the sealingmember, of a hydrogenated epoxy resin produced by hydrogenating anaromatic epoxy resin. This hydrogenated epoxy resin has a hydrogenationratio in an aromatic ring of not less than 85%, a loss ratio of epoxygroups of not more than 20%, and a total chlorine content of not morethan 0.3% by weight.

[0009] It is an object of the invention to provide a sealing memberwhich, while ensuring resistance to discoloration and resistance tocracking comparable to those in the invention described in JapanesePatent Laid-Open No. 196642/2001, has a novel composition provided byimproving the technique described in the prior application.

[0010] Further, in view of the fact that the discoloration of thesealing member is considered attributable to short-wavelength lightemitted from the light emitting element, as well as to heat generatedfrom the light emitting element, it is another object of the inventionto provide a sealing member which possesses excellent heat resistance inaddition to the resistance to discoloration and the resistance tocracking.

SUMMARY OF THE INVENTION

[0011] The present inventors have made extensive and intensive studieson the relationship between a light emitting element of a group IIInitride compound semiconductor and an epoxy resin. As a result, theyhave found that a mixture of an alicyclic epoxy produced byhydrogenating an aromatic epoxy and an alicyclic epoxy having a lowermolecular weight than the alicyclic epoxy described just above in agiven mixing ratio can provide a sealing member which has highresistance to light and heat and is less likely to be deteriorated. Theinvention has been made based on such finding and has the followingconstruction.

[0012] Specifically, according to the invention, there is provided alight emitting apparatus comprising:

[0013] a group III nitride compound semiconductor light emittingelement; and

[0014] a sealing member for covering the light emitting element on itslight emission side,

[0015] said sealing member comprising

[0016] a main agent comprising a first component of an alicyclic epoxyproduced by hydrogenating an aromatic epoxy and a second component of analicyclic epoxy having a lower molecular weight than the firstcomponent, the mixing amount of the second component being not less than10% by weight and less than 30% by weight based on the main agent, and

[0017] a curing agent.

[0018] According to the light emitting apparatus having the aboveconstruction, when a mixture of the first component and the secondcomponent in a predetermined ratio is used as the main agent of thesealing member, excellent mechanical and physical properties can beensured while maintaining the resistance to discoloration of the sealingmember.

[0019] In carrying out our invention in one preferred mode, when theacid anhydride is selected as the curing agent, the sealing member canbe of two-component type before curing. This can improve workingproperties particularly at the time of molding of the sealing member.Consequently, the light emitting apparatus can be provided at low price.

[0020] Further, in another preferred mode, when the cationicpolymerization catalyst is selected as the curing agent, the sealingmember can be of one-component type before curing. This is suitable foruse of the epoxy resin as an adhesive (a, paste) for bonding the lightemitting element, for example, to, a lead frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be explained in more detail in conjunctionwith the appended drawings, wherein:

[0022]FIG. 1 is a graph showing the relationship of the mixing ratio,between the first component and the second component in the main agent,to the discoloration resistance;

[0023]FIG. 2 is a typical cross-sectional view showing the constructionof a light emitting apparatus in an embodiment of the invention;

[0024]FIG. 3 is a graph showing a change in retention of the totalluminous flux over time in Examples 1 to 8 of the invention andComparative Example 1;

[0025]FIG. 4 is a diagram showing a table of formulations in Examples 1to 8 and Comparative Example 1;

[0026]FIG. 5 is a graph showing a change in power of ultraviolet lightover time in Examples 6 to 11 of the invention;

[0027]FIG. 6 is a diagram showing a table of formulations in Examples 6to 11 of the invention;

[0028]FIG. 7 is a graph showing a change in retention of the totalluminous flux over time in Examples 12 to 18 of the invention andComparative Example 2; and

[0029]FIG. 8 is a diagram showing a table of formulations in Examples 12to 18 and Comparative Example 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Individual constituent elements of the invention will beexplained in detail.

First Component in Main Agent

[0031] An epoxy resin proposed in Japanese Patent Laid-Open No.199645/1999 may be used as the first component of an alicyclic epoxyproduced by hydrogenating an aromatic epoxy resin. This: epoxy resin isa hydrogenated epoxy resin which has been produced by hydrogenating anaromatic epoxy resin and has a hydrogenation ratio in an aromatic ringof not less than 85%, a loss ratio of epoxy groups of not more than 20%,and a total chlorine content of not more than 0.3% by weight.

[0032] Studies conducted by the present inventors have revealed that, asthe aromatic epoxy resin, a bisphenol A epoxy is more preferred than abisphenol F epoxy. One possible reason for this is that, in many cases,it is difficult to wholly hydrogenize benzene rings in the aromaticepoxy, and, when benzene rings have remained unhydrogenized, the F type,in which group —CH₂— is sandwiched between benzene rings, undergoes theelimination of H more easily than the A type in which group —C(CH₃)₂— issandwiched between benzene rings to form a quinoid structure.

[0033] A hydrogenation product of the bisphenol A epoxy is as follows.

[0034] Japanese Patent Laid-Open No. 199645/1999 in its portionsrelevant to the invention will be quoted in this paragraph forclarifying the disclosure of the invention.

[0035] (1) The invention relates to an epoxy resin compositioncontaining (A) a hydrogenated epoxy resin produced by hydrogenation ofan aromatic epoxy resin in which the hydrogenated epoxy resin has ahydrogenation ratio in an aromatic ring of not less than 85%, a lossratio of epoxy groups of not more than 20%, and a total chlorine contentof not more than 0.3% by weight, and (B) a curing agent for the epoxyresin.

[0036] (2) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to the above item (1), 0.01 to200 parts by weight of a curing agent for the epoxy resin is mixed with100 parts by weight of the hydrogenated epoxy resin.

[0037] (3) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to the above item (1) or (2),the hydrogenated epoxy resin is produced by dissolving an aromatic epoxyresin in an ether solvent to prepare a solution and subjecting thesolution to hydrogenation under pressure in the presence of a catalystcomprising rhodium or ruthenium supported on graphite.

[0038] (4) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to any one of the above items(1) to (3), the hydrogenated epoxy resin is a liquid epoxy resin whichis produced by hydrogenating a bisphenol A epoxy resin and which has aviscosity of not more than 2.5 Pa.s as measured at 25° C. with arotating viscometer.

[0039] (5) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to any one of the above items(1) to (3), the hydrogenated epoxy resin is produced by hydrogenating anovolak type epoxy resin having an epoxy equivalent in the range of 150to 230 and represented by the following chemical formulas 2-3.

[0040] wherein R¹, R², and R³ represent a hydrogen atom or an alkylgroup having 1 to 4 carbon atoms; n is a number of 0 to 10; and Zrepresents a hydrogen atom or formula

[0041] [Chemical Formula 3]

[0042] wherein R¹, R², and R³ represent a hydrogen atom or an alkylgroup having 1 to 4 carbon atoms.

[0043] (6) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to any one of the above items(1) to (5) the hydrogenated epoxy resin has a total chlorine content ofnot more than 0.3% by weight and a hydrolyzable chlorine content of notmore than 0.1% by weight.

[0044] (7) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to any one of the above items(1) to (6), the curing agent for the epoxy resin is a compound selectedfrom amines, acid anhydrides, polyhydric phenols, imidazoles, salts ofBrφnsted acids, dicyandiamides, hydrazides of an organic acid,polymercaptans, and organic phosphines.

[0045] (8) The invention relates to an epoxy resin composition, wherein,in the epoxy resin composition according to any one of the above items(1) to (7), the curing agent for the epoxy resin is such that not morethan 10% by weight of the whole curing agent is accounted for by anaromatic ring.

[0046] The invention of this application will be explained in moredetail.

[0047] Component (A): Hydrogenated Epoxy Resin

[0048] The hydrogenated epoxy resin as the component (A) in theinvention is produced by hydrogenating an aromatic epoxy resin in whichthe hydrogenated epoxy resin has a hydrogenation ratio in an aromaticring of not less than 85%, a lose ratio of epoxy groups of not more than20%, and a total chlorine content of not more than 0.3% by weight. Thehydrogenation ratio in the aromatic ring in the epoxy resin refers tothe proportion of the aromatic ring which has been converted to analiphatic ring and can be determined by nuclear magnetic resonanceanalysis. The loss ratio of epoxy groups refers to the proportion ofepoxy groups which have been hydrogenated and can be determined bytitration with perchloric acid. The total chlorine refers to the totalamount of organic chlorines and inorganic chlorines contained in theepoxy resin and can be determined by reacting chlorine in the epoxyresin with sodium biphenyl and then titrating the reaction product withsilver nitrate.

[0049] The content of hydrolyzable chlorine in the hydrogenated epoxyresin as the component (A) is preferably not more than 0.1% by weightfor use in sealing material applications in electronic components. Whenthe hydrogenation ratio of an aromatic ring is less than 85%, theweather resistance of the cured product of the epoxy resin is extremelyand disadvantageously deteriorated. When the loss ratio of epoxy groupsexceeds 20%, the heat resistance of the cured product of the epoxy resinis extremely and disadvantageously deteriorated. Further, when the totalchlorine content exceeds 0.3% by weight, the moisture resistance,electrical characteristics at high temperatures, and weather resistanceare deteriorated. Therefore, in this case, the hydrogenated epoxy resinis unsuitable for use as an epoxy resin for electrical and electronicmaterials.

[0050] (A Method for Producing Hydrogenated Epoxy Resin)

[0051] The hydrogenated epoxy resin as the component (A) in theinvention can be produced by selectively hydrogenating an aromatic epoxyresin under pressure in the presence of a catalyst. Examples of aromaticepoxy resins include: bisphenol epoxy resins such as diglycidyl ether ofbisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether ofbisphenol S; novolak epoxy resins such as phenol novolak epoxy, cresolnovolak epoxy, and hydroxybenzaldehyde phenol novolak epoxy; andpolyfunctional epoxy resins such as glycidyl ether oftetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone,and epoxidized polyvinylphenol.

[0052] Among them, bisphenol A epoxy resin and novolak epoxy resinrepresented by the following chemical formulas 2-3 are preferred fromthe viewpoint of low chlorine content:

[0053] wherein R¹, R², and R³ represent a hydrogen atom or an alkylgroup having 1 to 4 carbon atoms; n is a number of 0 to 10; and Zrepresents a hydrogen atom or formula

[0054] wherein R¹, R², and R³ represent a hydrogen atom or an alkylgroup having 1 to 4 carbon atoms.

[0055] For applications where a balance between heat resistance andmoisture resistance is particularly required, more preferred are ahydrogenated bisphenol A epoxy resin having a viscosity of not more than2.5 Pa.s as measured at 25° C. with a rotating vicometer and a novolakepoxy resin represented by the general formula (1), particularly anepoxy resin produced by hydrogenating an aromatic epoxy resin whereinR¹, R², and R³ represent a hydrogen atom or a methyl group and which hasan epoxy equivalent of 150 to 230.

[0056] The hydrogenated epoxy resin as the component (A) in theinvention is produced by selectively hydrogenating an aromatic ring inan ether-based organic solvent, such as tetrahydrofran or dioxane, inthe presence of a catalyst comprising rhodium or ruthenium supported ongraphite (hexagonal crystalline graphite). The graphite as the support(carrier) has a surface area in the range of not less than 10 m²/g tonot more than 400 m²/g. The reaction is carried out under conditions ofpressure 1 to 30 MPa, temperature 30 to 150° C., and reaction time 1 to20 hr. After the completion of the reaction, the catalyst is removed byfiltration, and the ether-based organic solvent is removed bydistillation under reduced pressure until the ether-based organicsolvent is substantially entirely absent in the system, wherebyhydrogenated epoxy resin is produced.

[0057] Component (B): Curing Agent for Epoxy Resin

[0058] The hydrogenated epoxy resin as the component (A) in theinvention can be cured with a curing agent for an epoxy resin. Curingagents for the epoxy resin as the component (B) usable in the inventioninclude conventional curing agents for epoxy resins, for example,

[0059] {circle over (1)} amines: aliphatic and alicyclic amines such asdiethylenetriamine, triethylenetetramine, tetraethylenepentamine,N-aminoethylpiperazine, isophoronediamine,bis(4-aminocyclohexyl)methane, bis(aminemethyl)cyclohexane,m-xylylenediamine, and3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5,5]undecane; aromatic aminessuch as metaphenylenediamine, diaminodiphenylmethane, anddiaminodiphenylsulfone; and tertiary amines such as benzyldimethylamine,2,4,6-tris(dimethylaminomethyl)phenol,1,8-diazabicyclo(5,4,0)undecene-7,1,5-diazabicyclo(4,3,0)nonene-5, andsalts thereof,

[0060] {circle over (2)} acid anhydrides: aromatic acid anhydrides suchas phthalic anhydride, trimellitic anhydride, and pyromelliticanhydride; and alicyclic acid anhydrides such as tetrahydrophthalicanhydride, methyltetrahydrophthalic anhydride, hexahydrophthalicanhydride, methylhexahydrophthalic anhydride, methylenedomethylenetetrahydrophthalic anhydride, dodecenylsuccinic anhydride, andtrialkyltetrahydrophthalic anhydride,

[0061] {circle over (3)} polyhydric phenols: catechol, resorcin,hydroquinone, bisphenol F, bisphenol A, bisphenol S, bisphenol, phenolnovolaks, cresol novolaks, novolak compounds of a divalent phenol suchas bisphenol A, trishydroxyphenyl methanes, aralkyl polyphenols,dicyclopentadiene polyphenols and the like.

[0062] {circle over (4)} polyaminoamides: polyaminoamides produced by acondensation reaction of the amines in the above item {circle over (1)}with a dimer acid, for example, Versamides (tradename) 140 and 125(grade name) manufactured by Henkel, Ltd. and the like, and

[0063] {circle over (5)} others: imidazole compounds such as2-methylimidazole, 2-ethyl-4-imidazole, and 2-phenylimidazole and saltsof these imidazole compounds; BF₃ complex compounds of amines; salts ofBrφnsted acids, such as aliphatic sulphonium salts and aromaticsulfonium salts; dicyandiamides; hydrazides of organic acids, such asadipic acid dihydrazide and phthalic acid dihydrazide; and organicphosphine compounds such as polymercaptans and triphenylphosphine; andthe like.

[0064] These curing agents for epoxy resins may be used solely or as acombination of two or more of them.

[0065] The curing agent for an epoxy resin is preferably used in such anamount that not more than 10% by weight of the whole curing agent isaccounted for by the aromatic ring. When the content of the aromaticring exceeds 10% by weight, the weather resistance of the cured productof the epoxy is disadvantageously deteriorated. The mixing ratio betweenthe hydrogenated epoxy resin as the component (A) and the curing agentfor an epoxy resin as the component (B) is such that the amount of thecuring agent for an epoxy resin as the component (B) is 0.01 to 200parts by weight, preferably 0.1 to 150 parts by weight, based on 100parts by weight of the hydrogenated epoxy resin as the component (A).When the mixing, ratio is outside the above-defined range, the balancebetween heat resistance and moisture resistance of the cured product ofepoxy resin is disadvantageously deteriorated.

Optional Components

[0066] The following components may be optionally mixed as additivesinto the epoxy resin composition of the invention.

[0067] {circle over (1)} Powdered reinforcing materials and filters, forexample, metal oxides such as aluminum oxide and magnesium oxide, metalcarbonates such as calcium carbonate and magnesium carbonate, silicon,compounds such as powdered diatomaceous earth, basic magnesium silicate,calcined clay, finely divided silica, fused silica, and crystallinesilica, metal hydroxides such as aluminum hydroxide, and other materialssuch as kaolin, mica, powdered quartz, graphite, molybdenum disulfide,etc., and, further, fibrous reinforcing materials and fillers, forexample, glass fibers, ceramic fibers, carbon fibers, alumina fibers,silicon carbide fibers, boron fibers, polyester fibers, polyamidefibers, etc. They may be mixed, into the epoxy resin composition, in anamount of 10 to 900 parts by weight based on 100 parts by weight intotal of the epoxy resin and the curing agent.

[0068] {circle over (2)} Colorants, pigments, flame retardants, forexample, titanium dioxide, iron black, molybdenum red, iron blue,ultramarine blue, cadmium yellow, cadmium red, antimony trioxide, redphosphorus, brominated compounds, triphenyl phosphate, etc. They may bemixed, into the epoxy resin composition, in an amount of 0.1 to 20 partsby weight based on 100 parts by weight in total of the epoxy resin andthe curing agent.

[0069] {circle over (3)} Further, various curable monomers, oligomers,and synthetic resins may be mixed for improving the properties of resinsin final coatings, adhesive layers, molded products and the like. Forexample, one of or a combination of two or more diluents for epoxyresins such as monoepoxy resins, phenol resins, alkyd resins, melamineresins, fluororesins, vinyl chloride resins, acrylic resins, siliconeresins, polyester resins and the like may be used. The mixing ratio ofthese resins is preferably such that properties inherent in the resincomposition of the invention are not sacrificed, that is, the amount ofthe above resins is not more than 50 parts by weight based on 100 partsby weight in total of the epoxy resin and the curing agent. According tothe invention, means usable for mixing the epoxy resin, the curing agentfor an epoxy resin, and optional components include melt mixing withheating, melt kneading by means of a roller or a kneader, wet mixingusing a suitable organic solvent, and dry mixing.

Second Component in Main Agent

[0070] The alicyclic epoxy as the second component has a lower molecularweight than the alicyclic epoxy as the first component produced byhydrogenating an aromatic epoxy.

[0071] The alicyclic epoxy as the second component having a lowermolecular weight acts to crosslink the alicyclic epoxy as the firstcomponent, thereby improving the heat resistance of the epoxy resin. Asa result, discoloration resistance is improved. Further, mechanical andphysical properties of the sealing member, that is, cracking resistance,can be improved.

[0072] The alicyclic epoxy as the second component is preferably onecontaining an epoxycyclohexenyl group, for example,3,4-epoxycyclohexenylmethyl 3′,4′-epoxycyclohexenecarboxylate (seechemical formula 4).

Mixing Ratio Between First Component and Second Component

[0073] The mixing ratio between the first component and the secondcomponent is preferably such that the content of the second component inthe main agent is not less than 10% by weight and less than 30% byweight.

[0074] As shown in FIG. 1, when the mixing ratio of the second componentis less than 10% by weight, the resistance to discoloration isunsatisfactory. On the other hand, when the mixing ratio of the secondcomponent is excessively high, the cracking resistance isunsatisfactory. For the above reason, in the invention, the upper limitof the mixing ratio of the second component is less than 30% by weight.

[0075]FIG. 1 shows the relationship of the mixing ratio, between thefirst component (tradename; Epikote YL 6663, manufactured by Japan EpoxyResins Co., Ltd.) and the second component (tradename: CELLOXIDE 2021 P,manufactured by Daicel, Chemical Industries, Ltd.) (see abscissa), tothe level of change in total luminous flux (total quantity of lightemitted from LED) after a high-temperature accelerated test (150° C., 24hr) (see ordinate).

[0076] The mixing ratio between the first component and the secondcomponent is more preferably such that the content of the secondcomponent in the main agent is not less than 10% by weight and not morethan 25% by weight, still more preferably not less than 10% by weightand less than 20% by weight.

Curing Agent

[0077] In one preferred mode of this invention, an acid anhydride isadopted as the curing agent.

[0078] The acid anhydride used as the curing agent preferably does notcontain any double bond in its structure from the viewpoint ofpreventing the discoloration of the curing agent per se.

[0079] Curing agents include, for example, 4-methylhexahydrophthalicanhydride (chemical formula 5).

[0080] The amount of the acid anhydride as the curing agent mixed ispreferably 50 to 120 parts by weight, more preferably 60 to 90 parts byweight, based on 100 parts by weight of the main agent.

[0081] In another preferred mode of this invention, a cationicpolymerization catalyst is used as the curing agent. When the cationicpolymerization catalyst is used, preferably, suitable antioxidant and/orphotostabilizer are selected and mixed into the cationic polymerizationcatalyst to minimize the discoloration of the epoxy resin.

[0082] The use of the cationic polymerization catalyst causes thecleavage of epoxy rings, and the cleaved epoxy groups are reacted witheach other to form an ether linkage. In general, the cationicpolymerization catalyst has neither activated species nor functionalspecies. Therefore, even when the cationic polymerization catalyst staysin the epoxy resin, this catalyst is inert to light emitted from thegroup III nitride compound semiconductor light emitting element.

[0083] Cationic polymerization catalysts of this type usable hereininclude well-known cationic polymerization catalysts, for example, oniumsalts, such as sulfonium salts, ammonium salts, and phosphonium salts,and silanol-aluminum complexes. Specific examples thereof includecationic polymerization catalysts described, for example, in JapanesePatent No. 2875479, Japanese Patent Laid-Open Nos. 289611/1990 and29609/1999.

[0084] The use of cationic polymerization catalysts based on sulfoniumsalts is more preferred.

[0085] The amount of the cationic polymerization catalyst mixed variesdepending upon the performance of the catalyst. Preferably, however, thecationic polymerization catalyst is mixed in an amount of 0.1 to 5.0% byweight, more preferably 0.5 to 1.5% by weight, based on the epoxy resin.

Other Assistants

[0086] Assistants described in the above-described Japanese PatentLaid-Open No. 274571/1999, can of course be used as other assistants inthe invention. Further, the present inventors have made studies onassistants with focus on photostabilizers. When the stabilizer containsa benzene ring, the benzene ring absorbs green or blue light. Therefore,when the amount of the benzene ring-containing stabilizer mixed islarge, there is a fear of emission efficiency being lowered.

[0087] According to studies conducted by the present inventors, when agreen or blue light emitting element (main emission wavelength peak: 550to 420 nm) is used, the amount of the stabilizer mixed is preferably notmore than 10% by weight, more preferably 0.1 to 5% by weight, still morepreferably about 0.2% by weight, based on the sealing member.

[0088] Such stabilizers include phenolic antioxidants such as BHT(dibutylhydroxytoluene) (chemical formula 6).

[0089] Additional stabilizers include phosphoric photostabilizers suchas HCA (chemical formula 7).

[0090] When the light emitting element emits ultraviolet light (mainemission wavelength peak: 400 to 360 nm), preferably, the benzenering-containing stabilizer as represented by chemical formula 6 orchemical formula 7 is not incorporated, because the benzene ringstrongly absorbs ultraviolet light resulting in the occurrence ofdiscoloration.

[0091] The following phosphors may also be added as additives.Specifically, one or at least two phosphors selected from ZnS:Cu, Au,Al, ZnS:Cu, Al, ZnS:Cu, ZnS:Mn, ZnS:Eu, YVO₄:Eu. YVO₄:Ce, Y₂O₂S:Eu, andY₂O₂S:Ce may be used. Here ZnS:Cu, Au, Al is a ZnS-basedphotoluminescence phosphor wherein ZnS is a matrix and has beenactivated with copper (Cu), gold (Au), and aluminum (Al). ZnS:Cu, Al,ZnS:Cu, ZnS:Mn, and ZnS:Eu are photoluminescence phosphors wherein ZnSis likewise a matrix and has been activated with copper and aluminum forZnS:Cu, Al, has been activated with copper for ZnS:Cu, has beenactivated with manganese (Mn) for ZnS:Mn, and has been activated witheuropium (Eu) for ZnS:Eu. Likewise, YVO₄:Eu and YVO₄:Ce are phosphorswherein YVO₄ is a matrix and has been activated with europium forYVO₄:Eu and has been activated with cerium (Ce) for YVO₄:Ce, andY₂O₂S:Eu and Y₂O₂S:Ce are phosphors wherein; Y₂O₂S is a matrix and hasbeen activated with europium for Y₂O₂S:Eu and has been activated withcerium for Y₂O₂S:Ce. These phosphors have an absorption spectrum forblue to green light and emit light with longer wavelengths thanexcitation wavelength.

[0092] Among the above phosphors, ZnS:Eu, YVO₄:Ce, and Y₂O₂S:Ce,emission wavelength against exciting light of blue to green is longerthan that of the other phosphors. That is, colors of light emitted fromthese phosphors have a higher level of redness than colors of lightemitted from the other phosphores. Therefore, light produced by mixinglight emitted from these phosphors with light emitted from the lightemitting element as a primary light source has a color which is closerto white. Thus, in order to emit light having a color which is closer towhite, the use, as the phosphor, of one or at least two members selectedfrom ZnS:Eu, YVO₄:Ce, and Y₂O₂S:Ce is preferred.

[0093] CaS:Eu may also be used as the phosphor. This phosphor providesred fluorescence.

[0094] Further, cerium-activated yttrium-aluminum-garnet-based phosphorsas disclosed in Japanese Patent No. 2927279 may be used. In this case,cerium activation may not have been carried out. In theyttrium-aluminum-garnet-based phosphors, at least one element selectedfrom the group consisting of lutetium (Lu), scandium (Sc), lanthanum(La), gadolinium (Gd), and samarium (Sm) may be substituted for a partor the whole of yttrium, or alternately, any one of or both gallium (Ga)and indium (In) may be substituted for a part or the whole of aluminum.More specifically, the phosphor may be represented by formula(RE_(1-x)Sm_(x))₃(Al_(y)Ga_(1-y))₅O₁₂:Ce wherein 0≦x<1, 0≦y≦1, and RErepresents at least one member selected from yttrium (Y) and gadolinium(Gd). In this case, preferably, light emitted from the group III nitridecompound semiconductor light emitting element has a peak wavelength at400 to 530 nm.

Molding of Sealing Member

[0095] A light transparent sealing member for surrounding the lightemitting element is formed using the epoxy resin produced in this way.The form of the sealing member is not particularly limited. Preferably,however, the sealing member is in a shell form which offers lens effect.The whole part of the sealing member is not necessarily formed of theepoxy resin according to the invention. For example, a construction mayalso be adopted wherein the light emitting element in its peripheralportion, which is most likely to be deteriorated, is formed of the epoxyresin according to the invention, while the other portion is formed ofother light transparent material.

[0096] At the time of the production of the sealing member, the curingagent and various assistants may be incorporated in one of or both themain agent and the curing agent.

Group III Nitride Compound Semiconductor

[0097] The group III nitride compound semiconductor is represented bygeneral formula Al_(x)Ga_(y)In_(1-X-Y)N, wherein 0≦x≦1, 0≦Y≦1, and0≦X+Y≦1, and includes the so-called binary compound semiconductors, suchas AlN, GaN, and InN, and the so-called ternary compound semiconductorsrepresented by formulae Al_(x)Ga_(1-x)N wherein 0<x<1, Al_(x)In_(1-x)Nwherein 0<x<1, and Ga_(x)In_(1-x)N wherein 0<x<1. Boron (B), thallium(Tl), etc. may be substituted for at least a part of the group IIIelement(s). Further, phosphorus (P), arsenic (As), antimony (Sb),bismuth (Bi), etc. may be substituted for at least a part of nitrogen(N). The group III nitride compound semiconductor layer may contain anydopant. n-type impurities usable herein include silicon (Si), germanium(Ge), selenium (Se), tellurium (Te), and carbon (C). p-type impuritiesusable herein include magnesium (Mg), zinc (Zn), beryllium (Be), calcium(Ca), strontium (Sr), and barium (Ba). After doping with a p-typeimpurity, the group III nitride compound semiconductor may be exposed toelectron beams, plasma, or heat in an oven. This treatment, however, isnot indispensable. The group III nitride compound semiconductor layermay be formed by any method without particular limitation, for example,by well-known methods such as metal organic chemical vapor deposition(MOCVD), molecular beam epitaxy (MBE), halide vapor phase epitaxy(HVPE), sputtering, ion plating, and electron shower.

[0098] The light emitting element may have a homo structure, a heterostructure, or a double hetero structure. A quantum well structure (asingle quantum well structure or a multiple quantum well structure) mayalso be adopted.

Paste

[0099] The paste is an adhesive for fixing the light emitting element toa lead frame or the like. The above-described main agent and curingagent are used as a base, and various assistants are mixed into thebase. The addition of a reflective material such as silver can provide alight reflecting paste called “silver paste.” The addition of afluorescent material can realize wavelength conversion of light emittedfrom the light emitting element.

FIRST EXAMPLES

[0100] The construction and the effect in one preferred mode of theinvention will be explained in more detail in conjunction with thefollowing examples.

[0101] LED having a peak wavelength at about 485 nm provided by TOYODAGOSEI CO,, LTD. (applicant) was used as a light emitting element formedof a group III nitride compound semiconductor light emitting element.The LED has the following construction. Layer Composition p-type layerp-GaN:Mg Layer including light emitting layer Including InGaN layern-type layer n-GaN:Si Buffer layer AlN Substrate Sapphire

[0102] As shown in FIG. 2, a light emitting element 10 is mounted on acup-shaped part 33 provided in a lead frame 30 with the aid of anadhesive 20. The adhesive 20 is a silver paste produced by mixing silveras a filler into an epoxy resin. The use of the silver paste can improvedissipation of heat from the light emitting element 10. Otherconventional adhesives such as transparent pastes and white pastes maybe used instead of the silver paste.

[0103] A p electrode and an n electrode in the light emitting element 10are wire bonded to lead frames 31 and 30 through wires 41 and 40,respectively.

[0104] This light emitting element 10 was covered with a sealing member50 prepared in each of the following examples 1-8 and comparativeexample 1. The light emitting element 10 was continuously energizedunder conditions of 100° C. and 30 mA. In this case, a change in totalluminous flux (retention of total luminous flux) over time was measuredfor LED 1 shown in FIG. 2. The results are shown in FIG. 3.

[0105] Compositions of resins used in the examples 1-8 and thecomparative example 1 were as follows. All numeral values are in partsby weight. The compositions are tabulated in FIG. 4.

Example 1

[0106] An epoxy resin composition of Example 1 is a mixture of bisphenolA, which had been hydrogenated to bring the aromatic double bond to analicyclic ring (hereinafter referred to as “hydrogenated bis-A”), analicyclic epoxy having a lower molecular weight than the bis-A, and anacid anhydride as a curing agent. The detailed formulation of the epoxyresin composition is as follows. Epikote YL 6663¹⁾ 80 CELLOXIDE C 2021P²⁾ 20 PXE-4 ET³⁾ 1 Rikacid MH 700 G⁴⁾ 87.5

[0107]

Example 2

[0108] An epoxy resin composition of Example 2 is the same as the epoxyresin composition of Example 1, except that stabilizers have beenadditionally mixed into the epoxy resin composition. The details of thestabilizers are as follows. BHT⁵⁾ 0.1 HCA⁶⁾ 0.1

Example 3

[0109] An epoxy resin composition of Example 3 is the same as the epoxyresin composition of Example 2, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 0.2 HCA 0.2

Example 4

[0110] An epoxy resin composition of Example 4 is the same as the epoxyresin composition of Example 2, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 2 HCA 2

Example 5

[0111] An epoxy resin composition of Example 5 is the same as the epoxyresin composition of Example 2, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 4 HCA 4

Example 6

[0112] An epoxy resin composition of Example 6 is a mixture of a blendof hydrogenated bis-A's different from each other in epoxy equivalent,an alicyclic epoxy having a lower molecular weight than the bis-A's, andan acid anhydride as a curing agent. The detailed formulation of theepoxy resin composition is as follows. Epikote YL 6663 40 Epikote YL6834⁷⁾ 40 CELLOXIDE C 2021 P 20 PXE-4 ET 1 Rikacid MH 700 G 74.5 BHT 0.2HCA 0.2

Example 7

[0113] An epoxy resin composition of Example 7 is the same as the epoxyresin composition of Example 6, except that the mixing ratios of thehydrogenated bis-A's and the acid anhydride have been changed. Thedetails thereof are as follows. Epikote YL 6663 0 Epikote YL 6834 80Rikacid MH 700 G 64.5

Example 8

[0114] An epoxy resin composition of Example 8 is a mixture ofhydrogenated bis-A, an acid anhydride as a curing agent, andstabilizers. The detailed formulation of the epoxy resin composition ofExample 8 is as follows. Epikote YL 6834 100 PXE-4ET 1 Rikacid MH 700 G57.5 BHT 0.2 HCA 0.2

Comparative Example 1

[0115] An epoxy resin composition of Comparative Example 1 is a mixtureof bisphenol A (not hydrogenated), an alicyclic epoxy having a lowermolecular weight than the bisphenol A, an acid anhydride as a curingagent, and stabilizers. The detailed formulation of the epoxy resincomposition of Comparative Example 1 is as follows. Epikote 828 EL⁸⁾ 60CELLOXIDE C 2021 P 40 PXE-4ET 1 Rikacid MH 700 G 100 BHT 0.1 HCA 0.1

[0116] As is apparent from the results shown in FIG. 3, for the epoxyresin in each of the examples, a lowering in retention of the totalluminous flux over time is smaller than that for the epoxy resin in thecomparative example. In particular, in Examples 6, 7, and 8, there issubstantially no lowering in total luminous flux.

[0117] The epoxy resin compositions of Examples 6, 7, and 8 were usedwith an ultraviolet light (peak wavelength: 385 nm) emitting device, andthe change in retention of total luminous flux over time was studied.The results are shown in FIG. 5. In the experiment of which the resultsare shown in FIG. 5, the ultraviolet light emitting element was coveredwith a sealing member prepared in each of Examples 6, 7, and 8, and thelight emitting element was continuously energized under conditions of100° C. and 30 mA to measure the power of emitted ultraviolet light.

[0118] Separately, for Examples 9, 10, and 11 which are the same asExamples 6, 7, and 8 except for the absence of the stabilizer (see tablein FIG. 6), the retention of power of emitted ultraviolet light wasmeasured in the same manner as described above.

[0119] The results shown in FIG. 5 have revealed that the abovestabilizers greatly affect ultraviolet light. This demonstrates that theabove stabilizers are not preferably used in sealing members forultraviolet light emitting elements.

SECOND EXAMPLES

[0120] The construction and the effect in another preferred mode of theinvention will be explained in more detail in conjunction with thefollowing examples.

[0121] The light emitting element 10 which is the same as the firstexamples was covered with a sealing member 50 prepared in each of thefollowing examples 12-18 and comparative example 2. The light emittingelement 10 was continuously energized under conditions of 100° C. and 30mA. In this case, a change in total luminous flux (retention of totalluminous flux) over time was measured for LED 1 shown in FIG. 2. Theresults are shown in FIG. 7.

[0122] Compositions of resins used in the examples 12-18 and thecomparative example 2 were as follows. All numeral values are in partsby weight. The compositions are tabulated in FIG. 8.

Example 12

[0123] An epoxy resin composition of Example 12 is a mixture ofbisphenol A, which had been hydrogenated to bring the aromatic doublebond to an alicyclic ring (hereinafter referred to as “hydrogenatedbis-A”), an alicyclic epoxy having a lower molecular weight than thebis-A, and a cationic polymerization catalyst as a curing agent. Thedetailed formulation of the epoxy resin composition is as follows.Epikote YL 6663¹⁾ 80 CELLOXIDE C 2021P²⁾ 20 YLH 935³⁾ 0.5

Example 13

[0124] An epoxy resin composition of Example 13 is the same as the epoxyresin composition of Example 12, except that stabilizers have beenadditionally mixed. The details of the stabilizers are as follows. BHT⁵⁾0.05 HCA⁶⁾ 0.05

Example 14

[0125] An epoxy resin composition of Example 14 is the same as the epoxyresin composition of Example 13, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 0.1 HCA 0.1

Example 15

[0126] An epoxy resin composition of Example 15 is the same as the epoxyresin composition of Example 13, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 1 HCA 1

Example 16

[0127] An epoxy resin composition of Example 16 is the same as the epoxyresin composition of Example 13, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 2 HCA 2

Example 17

[0128] An epoxy resin composition of Example 17 is the same as the epoxyresin composition of Example 13, except that the mixing ratio of thestabilizers has been changed. The details of the mixing ratio are asfollows. BHT 2 HCA 0

Example 18

[0129] An epoxy resin composition of Example 18 is the same as the epoxyresin composition of Example 13, except that the mixing ratio of thestabilizers has been changed. The details, of the mixing ratio are asfollows. BHT 0 HCA 2

Comparative Example 2

[0130] An epoxy resin composition of Comparative Example 2 is a mixtureof bisphenol A (not hydrogenated), an alicyclic epoxy having a lowermolecular weight than the bisphenol A, a cationic polymerizationcatalyst as a curing agent, and stabilizers. The detailed formulation ofthe epoxy resin composition of Comparative Example 1 is as follows.Epikote 828 EL⁸⁾ 60 CELLOXIDE C 2021P 40 YLH 935 0.5 BHT 0.1 HCA 0.1

[0131] As is apparent from the results shown in FIG. 7, for the epoxyresin in each of the examples 12-18, a lowering in retention of thetotal luminous flux over time is smaller than that for the epoxy resinin the comparative example 2.

[0132] This invention is not limited to the above embodiments andexplanation thereof, and variations and modifications can be effectedwithin the scope which does not depart from the description in theclaims and can be easily conceived by a person having ordinary skill inthe art.

[0133] The following items will be disclosed.

[0134] (1) The light emitting apparatus according to any of claims 1 to5, wherein the light emitting element emits a light which has a mainemission peak at 550 to 420 nm and the sealing member contains not morethan 10% by weight of a stabilizer.

[0135] (2) The light emitting apparatus according to any of claims 1 to5, wherein the light emitting element emits a light which has a mainemission peak in an ultraviolet region and the sealing member does notcontain any benzene ring-containing stabilizer.

[0136] (3) A light emitting apparatus comprising:

[0137] a group III nitride compound semiconductor light emittingelement; and

[0138] a die bonding paste,

[0139] said paste comprising

[0140] a main agent comprising a first component of an alicyclic epoxyproduced by hydrogenating an aromatic epoxy and a second component of analicyclic epoxy having a lower molecular weight than the firstcomponent, the mixing amount of the second component being not less than10% by weight and less than 30% by weight based on the main agent, and

[0141] a curing agent.

[0142] (4) The light emitting apparatus according to the above item 3,wherein the curing agent consists essentially of an acid anhydride.

[0143] (5) The light emitting apparatus according to the above item 3,wherein the curing agent consists essentially of a cationicpolymerization catalyst.

[0144] (6) The light emitting apparatus according to any of the aboveitems 3 to 5, wherein the aromatic epoxy is a bisphenol A epoxy.

[0145] (7) The light emitting apparatus according to any of the aboveitems 3 to 6, wherein the first component in the main agent has ahydrogenation ratio in an aromatic ring of not less than 85%, a lossratio of epoxy groups of not more than 20%, and a total chlorine contentof not more than 0.3% by weight.

[0146] (8) The light emitting apparatus according to any of the aboveitems 3 to 7, wherein the mixing amount of the second component in themain agent is 10 to 25% by weight.

[0147] (9) The light emitting apparatus according to any of the aboveitems 3 to 8, wherein the light emitting element emits a light which hasa main emission peak wavelength of not more than 550 nm.

[0148] (10) The light emitting apparatus according to any of the aboveitems 3 to 9, wherein the light emitting element emits a light which hasa main emission peak at 550 to 420 nm and the paste contains not morethan 10% by weight of a stabilizer.

[0149] (11) The light emitting apparatus according to any of the aboveitems 3 to 10, wherein the light emitting element emits a light whichhas a main emission peak in an ultraviolet region and the paste does notcontain any benzene ring-containing stabilizer.

[0150] (12) A sealing member for a light emitting element comprising:

[0151] a main agent comprising a first component of an alicyclic epoxyproduced by hydrogenating an aromatic epoxy and a second component of analicyclic epoxy having a lower molecular weight than the firstcomponent, the mixing amount of the second component being not less than10% by weight and less than 30% by weight based on the main agent; and

[0152] a curing agent.

[0153] (13) The sealing member according to the above item 12, whereinthe curing agent consists essentially of an acid anhydride.

[0154] (14) The sealing member according to the above item 12, whereinthe curing agent consists essentially of a cationic polymerizationcatalyst.

[0155] (15) The sealing member according to any of the above items 12 to14, wherein the aromatic epoxy is a bisphenol A epoxy.

[0156] (16) The sealing member according to any of the above items 12 to15, wherein the first component in the main agent has a hydrogenationratio in an aromatic ring of not less than 85%, a loss ratio of epoxygroups of not more than 20%, and a total chlorine content of not morethan 0.3% by weight.

[0157] (17) The sealing member according to any of the above items 12 to16, wherein the mixing amount of the second component in the main agentis 10 to 25% by weight.

[0158] (18) The sealing member according to any of the above items 12 to17, wherein the light emitting element emits a light which has a mainemission peak wavelength of not more than 550 nm.

[0159] (19) The sealing member according to any of the above items 12 to18, wherein the light emitting element emits a light which has a mainemission peak at 550 to 420 nm and the sealing member contains not morethan 10% by weight of a stabilizer.

[0160] (20) The sealing member according to any of the above items 12 to19, wherein the light emitting element emits a light which has a mainemission peak in an ultraviolet region and the sealing member does notcontain any benzene ring-containing stabilizer.

[0161] (21) A paste for die bonding of a light emitting elementcomprising:

[0162] a main agent comprising a first component of an alicyclic s epoxyproduced by hydrogenating an aromatic epoxy and a second component of analicyclic epoxy having a lower molecular weight than the firstcomponent, the mixing amount of the second component being not less than10% by weight and less than 30% by weight based on the main agent; and

[0163] a curing agent.

[0164] (22) The paste for die bonding of a light emitting elementaccording to the above item 21, wherein the curing agent consistsessentially of an acid anhydride.

[0165] (23) The paste for die bonding of a light emitting elementaccording to the above item 21, wherein the curing agent consistsessentially of a cationic polymerization catalyst.

[0166] (24) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 23, wherein the aromatic epoxyis a bisphenol A epoxy.

[0167] (25) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 24, wherein the firstcomponent in the main agent has a hydrogenation ratio in an aromaticring of not less than 85%, a loss ratio of epoxy groups of not more than20%, and a total chlorine content of not more than 0.3% by weight.

[0168] (26) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 25, wherein the mixing amountof the second component in the main agent is 10 to 25% by weight.

[0169] (27) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 26, wherein the light emittingelement emits a light which has a main emission peak wavelength of notmore than 550 nm.

[0170] (28) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 27, wherein the light emittingelement emits a light which has a main emission peak at 550 to 420 nmand the sealing member contains not more than 10% by weight of astabilizer.

[0171] (29) The paste for die bonding of a light emitting elementaccording to any of the above items 21 to 28, wherein the light emittingelement emits a light which has a main emission peak in an ultravioletregion and the sealing member does not contain any benzenering-containing stabilizer.

What is claimed is:
 1. A light emitting apparatus comprising: a groupIII nitride compound semiconductor light emitting element; and a sealingmember for covering the light emitting element on its light emissionside, said sealing member comprising a main agent comprising a firstcomponent of an alicyclic epoxy produced by hydrogenating an aromaticepoxy and a second component of an alicyclic epoxy having a lowermolecular weight than the first component, the mixing amount of thesecond component being not less than 10% by weight and less than 30% byweight based on the main agent, and a curing agent.
 2. The lightemitting apparatus according to claim 1, wherein the curing agentconsists essentially of an acid anhydride.
 3. The light emittingapparatus according to claim 1, wherein the curing agent consistsessentially of a cationic polymerization catalyst.
 4. The light emittingapparatus according to claim 1, wherein the aromatic epoxy is abisphenol A epoxy.
 5. The light emitting apparatus according to claim 1,wherein the first component in the main agent has a hydrogenation ratioin an aromatic ring of not less than 85%, a loss ratio of epoxy groupsof not more than 20%, and a total chlorine content of not more than 0.3%by weight.
 6. The light emitting apparatus according to claim 1, whereinthe mixing amount of the second component in the main agent is 10 to 25%by weight.
 7. The light emitting apparatus according to claim 1, whereinthe light emitting element emits a light which has a main emission peakwavelength of not more than 550 nm.
 8. The light emitting apparatusaccording to claim 1, wherein the light emitting element emits a lightwhich has a main emission peak at 550 to 420 nm and the sealing membercontains not more than 10% by weight of a stabilizer.
 9. The lightemitting apparatus according claim 1, wherein the light emitting elementemits a light which has a main emission peak in an ultraviolet regionand the sealing member does not contain any benzene ring-containingstabilizer.
 10. A light emitting apparatus comprising: a group IIInitride compound semiconductor light emitting element; and a paste forfixing a substrate of the light emitting element, said paste comprisinga main agent comprising a first component of an alicyclic epoxy producedby hydrogenating an aromatic epoxy and a second component of analicyclic epoxy having a lower molecular weight than the firstcomponent, the mixing amount of the second component being not less than10% by weight and less than 30% by weight based on the main agent, and acuring agent.
 11. The light emitting apparatus according to claim 10,wherein the curing agent consists essentially of an acid anhydride. 12.The light emitting apparatus according to claim 10, wherein the curingagent consists essentially of a cationic polymerization catalyst.
 13. Asealing member for a light emitting element comprising: a main agentcomprising a first component of an alicyclic epoxy produced byhydrogenating an aromatic epoxy and a second component of an alicyclicepoxy having a lower molecular weight than the first component, themixing amount of the second component being not less than 10% by weightand less than 30% by weight based on the main agent; and a curing agent.14. The sealing member for a light emitting element according to claim13, wherein the curing agent consists essentially of an acid anhydride.15. The sealing member for a light emitting element according to claim13, wherein the curing agent consists essentially of a cationicpolymerization catalyst.
 16. The sealing member for a light emittingelement according to claim 13, wherein the aromatic epoxy is a bisphenolA epoxy.
 17. The sealing member for a light emitting element accordingto claim 13, wherein the first component in the main agent has ahydrogenation ratio in an aromatic ring of not less than 85%, a lossratio of epoxy groups of not more than 20%, and a total chlorine contentof not more than 0.3% by weight.
 18. The sealing member for a lightemitting element according to claim 13, wherein the mixing amount of thesecond component in the main agent is 10 to 25% by weight.
 19. Thesealing member for a light emitting element according to claim 13,wherein the light emitting element emits a light which has a mainemission peak at 550 to 420 nm and the sealing member contains not morethan 10% by weight of a stabilizer.
 20. The sealing member for a lightemitting element according to claim 13, wherein the light emittingelement emits a light which has a main emission peak in an ultravioletregion and the sealing member does not contain any benzenering-containing stabilizer.